BR112016016809B1 - PARAMETERS FOR DEVICE-TO-DEVICE DISCOVERY - Google Patents

Abstract

PARAMETERS FOR DEVICE-TO-DEVICE DISCOVERY. User device may receive one or more parameters from a base station to facilitate device-to-device (D2D) discovery. One of the received parameters is a discovery period parameter, which identifies a discovery period in which discovery resources are available for D2D discovery. Once the user device has received the parameters, the user device can use the parameters to participate in D2D discovery.

Description

CROSS REFERENCES

[0001] The present patent application claims priority for US patent application No. 14/556,996 by Baghel et al., entitled “PARAMETERS FOR DISPOSITIVO TO DISPOSITIVO DISCOVERY,” filed December 1, 2014; and US Provisional Patent Application No. 61/929,895 by Baghel et al, entitled "PARAMETERS FOR DISPOSITIVO TO DISPOSITIVO DISCOVERY ", deposited on January 21, 2014, each of which is attributed to the depositor thereof.

BACKGROUND OF THE INVENTION FIELD OF THE INVENTION

[0002] Wireless communication systems are widely used to provide various types of communication content such as voice, video, packet data, e-mail communication, transmission, etc.

STATE OF TECHNICAL DESCRIPTION

[0003] Wireless communication systems can be multiple-access systems capable of supporting communication with multiple users by sharing available system resources (eg, time, frequency, and energy). Examples of such multiple access systems include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, and multiple access systems Orthogonal Frequency Division (OFDMA). In general, a Wireless Multiple Access Communication System may include a number of base stations, each simultaneously supporting communication to multiple user devices. Base stations can communicate with user devices on upstream and downstream links. Each base station has a range of coverage, which may be called the base station or cell coverage area.

[0004] User devices that are close together can also communicate directly via device-to-device (D2D) communication. To do so, however, a user device first discovers the other user devices that are in range for D2D communication. The D2D discovery process allows a user device to broadcast a discovery signal to announce that the user device is available to be discovered. Additionally, the user device receives and decodes discovery signals from other user devices that are in range. However, in order for a D2D transmission to be received and decoded, receiving user devices may need to have an understanding of the timing and method by which the transmitting user device is transmitting its discovery signal.

SHORT DESCRIPTION OF THE INVENTION

[0005] The characteristics described generally refer to one or more improved methods, systems, or equipment for managing wireless communications. As an example, a first method for wireless communication is described. In one configuration, a user device receives from a base station one or more parameters that enable D2D discovery. One of the parameters received is a discovery period parameter, which identifies a discovery period in which discovery resources are available for D2D discovery. Once the user device has received the parameters, the user device uses the parameters to participate in D2D discovery.

[0006] According to a first set of illustrative embodiments, a method for wireless communication may include receiving at a user device a plurality of parameters for device-to-device discovery, where the plurality of parameters including a period parameter discovery period identifying a discovery period in which discovery resources are available for device-to-device discovery. The method may also include using the plurality of parameters to participate in discovery with other user devices. In some examples, the discovery period is a fraction or multiple of a maximum system frame number (SFN) of a network on which the user device is used. When the discovery period is a multiple of a maximum SFN, the plurality of parameters may also include an SFN length parameter to indicate a number of times the maximum SFN is exceeded during the discovery period.

[0007] In certain examples, the plurality of parameters may also include a discovery offset parameter indicating an offset between a start of the discovery period and a fixed time-based reference point for both transmit and receive groups. In some examples, a neighbor receiving group offset may also be indicated with respect to the fixed reference point of a serving cell. In other examples, the plurality of parameters may also include a discovery subframes parameter indicating which subframes within the discovery period are available as discovery resources. The discovery subframes parameter can be a bitmap. Additionally, the plurality of parameters may also include a discovery resource block (RB) length parameter indicating a number of RBs to be used for each discovery signal within a subframe available as a discovery resource. Furthermore, the plurality of parameters may also include discovery start and end point RB parameters indicating a start point and an end point of a number of resource blocks to be used for each discovery signal within a subframe available as a resource. of discovery.

[0008] In certain examples, a plurality of parameters may also include modulation and encoding parameters indicating a modulation and encoding scheme for transmission of discovery signal. In certain other examples, the plurality of parameters may also include a sync signal parameter position indicating a position of a base station sync signal as sent each discovery period by one or more user devices connected to the base station. .

[0009] In certain examples, the plurality of parameters may also include a transmit power parameter indicating a power level for transmitting discovery signal. The transmit power parameter may be a plurality of transmit power parameters when resources used for discovery are divided into different power zones. Each of the plurality of transmit power parameters can be associated with a corresponding power zone and presents an associated bitmap indicating subframes used for discovery signal transmission at the respective power level.

[00010] In certain examples, the plurality of parameters may also include an authorized mode of operation parameter indicating whether discovery may occur during a connected mode or an idle mode. The plurality of parameters may also include a common discovery resource pool parameter or a dedicated discovery resource pool parameter indicating whether discovery resources are common to user devices or whether discovery resources are dedicated to specific user devices. The dedicated or common discovery resource pool parameter can be a bitmap indicating start and end points of common or dedicated discovery resources when the discovery resources are frequency domain multiplexing (FDM). Alternatively, the common discovery resource pool parameter is a first bitmap indicating common discovery resources and the dedicated discovery resource pool parameter is a second bitmap indicating second bitmap when the discovery resources are multiplexing by time domain (TDM).

[00011] In certain examples, the plurality of parameters may also include a transmission resource selection method parameter indicating a method to be used by the user device for selecting which of the available discovery resources should be used for signal transmission of discovery. In certain other examples, the plurality of parameters may also include a demodulation reference signal useful cyclic changes (DMRS) parameter indicating that DMRS cyclic changes are available as a time-varying pattern of DMRS Alteration.

[00012] In certain examples, some of the plurality of parameters are different based on a class of user devices. For example, the plurality of parameters includes two or more of a system frame number (SFN) length parameter, a discovery offset parameter, a discovery subframes parameter, a discovery resource block length parameter , discovery resource block starting point and endpoint parameters, modulation and encoding parameters, a sync signal parameter position, a transmit power parameter, an authorized mode of operation parameter, a common discovery resource pool, and a dedicated discovery resource pool parameter. The user device class can be either commercial safety or public safety.

[00013] In certain examples, the discovery period parameter is different for different classes of user devices. The plurality of parameters may also include one or more discovery offset parameters for different classes of user devices, the discovery offset parameters respectively indicating an offset between a start of a respective discovery period and a reference point based on in the fixed time. In some examples, the discovery offset parameters indicate an offset between the start of the respective discovery period and the fixed time-based reference point for both transmit and receive groups. In some examples, a neighbor reception group offset may also be indicated with respect to a fixed reference point of a serving cell of the user device. The plurality of parameters may also include one or more discovery resource block (RB) length parameters for the different classes of user devices, the discovery RB parameters respectively indicating a number of RBs to be used for each discovery signal within of a subframe available as a discovery feature. The plurality of parameters may also include modulation and encoding parameters indicating modulation and encoding schemes for transmitting the discovery signal to each of the different classes of user devices.

[00014] In certain examples, the method for wireless communication may include performing a hashing operation using a system time and security key to encode the discovery with other user devices. Furthermore, the method may include receiving the system time as one of the plurality of parameters. The plurality of parameters may include a parameter indicating a number of discovery signal transmissions to be made by the user device when discovery capabilities are dedicatedly provided to the user device. The plurality of parameters may also include a parameter indicating an empty discovery signal transmission number by which the user device may determine which discovery resources previously dedicated to the user device are deallocated.

[00015] In certain examples, reception of the plurality of parameters also includes reception of some of the plurality of parameters on different frequencies in a system broadcast message. In other examples, receiving the plurality of parameters also includes receiving the plurality of parameters for different public land mobile networks (PLMNs) in a system broadcast message.

[00016] According to a second set of illustrative embodiments, an apparatus for wireless communication may include means for receiving in a user device a plurality of parameters for device-to-device discovery, the plurality of parameters including a parameter of discovery period identifying a discovery period in which discovery resources are available for device-to-device discovery. The apparatus may also include means for utilizing the plurality of parameters in order to participate in discovery with other user devices.

[00017] In certain examples, the means for receiving may include means for receiving an SFN length parameter to indicate a number of times a maximum SFN is exceeded during the discovery period. In certain examples, the means for receiving may include means for receiving a discovery offset parameter indicating an offset between a start of the discovery period and a fixed time-based reference point. In certain examples, the means for receiving may include means for receiving a discovery subframe parameter indicating which subframes within the discovery period are available as discovery resources. The means for receiving may include means for receiving a discovery RB length parameter indicating a number of RBs to be used for each discovery signal within a subframe available as a discovery resource. The means for receiving may also include means for receiving discovery RB start and end point parameters indicating a start point and an end point of the RBs to be used for each discovery signal within a subframe available as a discovery facility.

[00018] According to another set of illustrative embodiments, an apparatus configured for wireless communication can include at least one processor and memory coupled to at least one processor. The at least one processor may be configured to receive at a user device a plurality of parameters for device-by-device discovery, the plurality of parameters including a discovery period parameter identifying a discovery period in which discovery resources are available for device-to-device discovery. The at least one processor may also be configured to utilize the plurality of parameters in order to participate in discovery with other user devices.

[00019] In certain examples, the processor may also be configured to receive an SFN extension parameter to indicate a number of times a maximum SFN is exceeded during the discovery period. In certain other examples, the processor may also be configured to receive a discovery offset parameter indicating an offset between a start of the discovery period and a fixed time based reference point. The processor can also be configured to receive a discovery subframes parameter indicating which subframes within the discovery period are available as discovery resources. The processor may also be configured to receive a discovery RB length parameter indicating a number of RBs to be used for each discovery signal within a subframe available as a discovery resource. In certain other examples, the processor may also be configured to receive discovery RB start and end point parameters indicating a start point and an end point of the RBs to be used for each discovery signal within a subframe available as a discovery facility. . In certain examples, the plurality of parameters also include a transmit power parameter indicating a power level for transmitting the discovery signal. In other examples, the transmit power parameter may be a plurality of transmit power parameters when resources used for discovery are divided into different power zones, each of the plurality of transmit power parameters being associated with a power zone. and having an associated bitmap indicating subframes used for discovery signal transmission at the respective power level.

[00020] According to another set of illustrative embodiments, a computer program product may include a non-transient computer-readable medium having non-transient program code recorded therein. The non-transient program code may include program code for receiving at a user device a plurality of parameters for device-to-device discovery, the plurality of parameters including a discovery period parameter identifying a discovery period at which Discovery features are available for device-to-device discovery. The non-transient program code may also include program code for utilizing the plurality of parameters to participate in discovery with other user devices. In certain examples, the program code may also include program code to receive an SFN extension parameter to indicate a number of times a maximum SFN is exceeded during the discovery period. In certain other examples, the program code may also include program code for receiving a discovery offset parameter indicating an offset between a start of the discovery period and a reference point based on the fixed time. Optionally, the program code can also include program code to receive a discovery subframes parameter indicating which subframes within the discovery period are available as discovery resources. In certain examples, the program code may also include program code for receiving a discovery RB length parameter indicating a number of RBs to be used for each discovery signal within a subframe available as a discovery resource. The program code may also include program code for receiving discovery RB start and end point parameters indicating a start point and an end point of the RBs to be used for each discovery signal within a subframe available as a discovery facility.

[00021] According to another set of illustrative embodiments, a method for wireless communication may include transmitting to a plurality of user devices a plurality of parameters for device-to-device discovery, the plurality of parameters including a parameter discovery period identifying a discovery period, in which discovery resources are available for device-to-device discovery.

[00022] In certain examples, the discovery period may be a multiple of a maximum SFN, the plurality of parameters passed to user devices also include an SFN extension parameter to indicate a number of times the maximum SFN is exceeded during the discovery period. In other examples, the plurality of parameters passed to user devices may also include a discovery offset parameter indicating an offset between a start of the discovery period and a fixed time-based reference point.

[00023] In certain examples, the plurality of parameters passed to user devices may also include a discovery subframes parameter indicating which subframes within the discovery period are available as discovery resources. The plurality of parameters transmitted to user devices may also include a discovery RB length parameter indicating a number of RBs to be used for each discovery signal within a subframe available as a discovery resource. In certain examples, the plurality of parameters passed to user devices may also include discovery RB start and end point parameters indicating a start point and an end point of the RBs to be used for each discovery signal within a subframe available as a discovery feature. In certain examples, the method may include repeating the transmission of the plurality of parameters for different frequencies in a system transmission message. Additionally, in certain examples, the method may include repeating transmissions of the plurality of parameters to different public land mobile networks (PLMNs) in a system transmission message.

[00024] The further scope of applicability of the described methods and apparatus will become apparent from the following detailed description, claims and drawings. The detailed description and specific examples are given by way of illustration only, as various changes and modifications within the scope of the description will become apparent to one skilled in the art.

BRIEF DESCRIPTION OF THE DRAWINGS

[00025] A better understanding of the nature and advantages of the present description can be accomplished by reference to the following drawings. In the attached figures, similar components or characteristics may have the same reference label. Furthermore, several components of the same type can be distinguished by following this reference label by a dash label and a second label that distinguishes between similar components. If only the first reference label is used in the specification, the description is applicable to any of the similar components having the same first reference label irrespective of the second reference label. Figure 1 is a block diagram and example of a wireless communication system, in accordance with various embodiments; Figure 2 is a block diagram of an exemplary system for device-to-device discovery and wireless communication, in accordance with various embodiments; Figure 3 is a block diagram of an example of a discovery system information block (SIB), in accordance with various embodiments; 4A is a message flow chart illustrating exemplary communications between user devices engaging in device-to-device discovery, in accordance with various embodiments; Figure 4B is a block diagram illustrating exemplary communications between user devices engaging device-to-device discovery, in accordance with various embodiments; Figure 5 is a block diagram of an example of a user device, in accordance with various embodiments; Figure 6 is a block diagram of an example of a user device peer discovery module, in accordance with various embodiments; Figure 7 is a block diagram of an example of a discovery period module, in accordance with various embodiments; Figure 8 is a block diagram of an example of a user device, in accordance with various embodiments; Figure 9 is a block diagram of an example of a base station, in accordance with various embodiments; Figure 10 is a block diagram of an example of a discovery parameters module in a base station, in accordance with various embodiments; and Figures 11-15 are flowcharts of various methods for wireless communication, in accordance with various embodiments.

DETAILED DESCRIPTION

[00026] Typically, user devices engage in wireless communication by communicating with a base station of a wireless communication system. However, users of user devices can also participate in wireless D2D communication. D2D wireless communication allows user devices that are in range of each other to communicate directly with each other rather than communicating through a base station. An example of when D2D wireless communication is desired is when a user device leaves coverage of a base station. To avoid an interruption in service, the user device, which has left the coverage area, can transmit a peer discovery message such as a discovery signal - Direct Peer in a Long Term Evolution (LTE) system which can then be received by a user device in coverage. Once the two user devices have discovered each other, the user device in coverage can act as a relay between the user device out of coverage and the base station. Other uses of D2D wireless communications also exist. D2D wireless communication, however, can be dependent on user devices discovering each other via a D2D discovery process. The D2D discovery process can be coordinated such that each user device is configured with sufficient parameters to discover other user devices.

[00027] The following description provides examples, and is not restrictive of the scope, applicability or configuration established in the claims. Changes may be made to the function and arrangement of elements without thereby departing from the scope of the description. Various embodiments may omit, substitute, or add various procedures or components as appropriate. For example, the methods described can be performed in a different order than described, and multiple steps can be added, omitted, or combined. Also, features described with respect to certain embodiments can be combined in other embodiments.

[00028] Referring first to Figure 1, a diagram illustrates an example of a wireless communication system 100. The wireless communication system 100 includes base stations (or cells) 105, communication devices 115, and a network of core 130. Base stations 105 may communicate with communication devices 115 under the control of a base station controller which may be part of the core network 130 or the base stations 105 in various embodiments. Base stations 105 can communicate control information or user data with the core network 130 via backlinks 132. In embodiments, Base Stations 105 can communicate either directly or indirectly with each other via backlinks 134, which can be wired or wireless communication links. System 100 can support operation on multiple carriers (conda-shaped signals of different frequencies). Multi-carrier transmitters can transmit modulated signals simultaneously on multiple carriers. For example, each communication link 125 can be a multi-carrier modulated signal in accordance with the various radio technologies described above. Each modulated signal can be sent to a different carrier and can carry control information (eg, reference signals, control channels, etc.), header information, data, and the like.

[00029] The base stations 105 can communicate wirelessly with the user devices 115 via one or more base station antennas. Each of the base station sites 105 may provide communication coverage for a respective coverage area 110. In some embodiments, the base station 105 may be called a base transceiver station, a radio base station, a point access point, a radio transceiver, a basic service set (BSS), an extended service set (ESS), a NodeB, an eNodeB (eNB), a Home NodeB, a Home eNodeB, or some other suitable terminology. The coverage area 110 for a base station 105 may be divided into sectors that make up only a portion of the coverage area. System 100 may include Base Stations 105 of different types (e.g. macro, micro, or pico base stations). There may be overlapping coverage areas for different technologies.

[00030] In embodiments, the system 100 is an LTE/LTE-A network. In LTE/LTE-A networks, the terms evolved Node B (eNB) and user equipment (UE) may generally be used to describe Base Stations 105 and User Devices 115, respectively. System 100 may be a heterogeneous LTE/LTE-A network in which different types of Base Stations 105 provide coverage for various geographic regions. For example, each base station 105 can provide communication coverage for a macro cell, a pico cell, a femto cell, or other cell types. A macro cell generally covers a relatively large geographic area (eg, several kilometers in radius) and may allow unrestricted access by user devices 115 with service subscriptions with the network provider. The pico cell generally covers a relatively smaller geographic area and may allow unrestricted access by user devices 115 with service subscriptions with the network provider. The femto cell in general may also cover a relatively small geographic area (e.g. a home) and, in addition to unrestricted access, may also provide restricted access by user devices 115 having an association with the femto cell (e.g. user devices in a closed subscriber group (CSG), user devices for home users, and the like). The base station 105 for a macro cell may be called an eNB macro. For example, the base station 105 for a pico cell may be called a pico eNB. And a base station 105 for a femto cell can be called a femto eNB or a home eNB. Base station 105 can support one or multiple cells (e.g., two, three, four, etc.).

[00031] The core network 130 can communicate with the base stations 105 via backlinks 132 (eg, SI, etc.). Base stations 105 may also communicate with each other, for example, directly or indirectly via backlinks 134 (eg, X2, etc.) or via backlinks 132 (eg, via core network 130). Wireless communication system 100 can support synchronous or asynchronous operation.

[00032] For synchronous operation, the base stations 105 can exhibit similar frame synchronization, and transmissions from different base stations 105 can be approximately time-aligned. For asynchronous operation, Base Stations 105 may have different frame timings, and transmissions from different Base Stations 105 may not be time-aligned. The techniques described here can be used for both synchronous and asynchronous operations.

[00033] Base Stations 105 may also communicate their frame synchronization and other parameters to user devices 115. In this way, wireless communication between Base Stations 105 and user devices 115 may include transmission of various commands and parameters . Among the parameters that may be communicated from a base station 105 to a user device 115 are those that allow user device 115 to participate in D2D discovery. These discovery parameters in your communication are also explained in the following embodiments.

[00034] The user devices 115 are dispersed throughout the wireless communication system 100, and each user device 115 can be stationary or mobile. A user device 115 may also be referred to by the person skilled in the art as a UE, a mobile device, a mobile station, a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a wireless device, a wireless communication device, a remote device, a mobile subscriber station, an access terminal, a mobile terminal, a wireless terminal, a remote terminal, a telephone set, a user agent, a mobile client, a client, a relay or some other suitable terminology. A user device 115 can be a cellular phone, a personal digital assistant (PDA), a wireless modem, a wireless communication device, a handheld device, a tablet computer, a laptop computer, a cordless phone, a dock wireless local loop (WLL) or similar. A user device 115 may be able to communicate with macro eNBs, pico eNBs, femto eNBs, relays, and the like. A user device 115-a may also directly communicate with another user device 115 via D2D wireless communication. In one example, a user device 115 within a coverage area 110 of a base station 105 can serve as a relay for a user device 115-a that is outside the coverage area 110 of the base station 105. in-coverage user device 115 may relay communications from base station 105 to out-of-coverage user device 115-a.

[00035] Similarly, the in-coverage user device 115 may relay communications from the out-of-coverage user device 115-a to the base station 105.

[00036] For a user device 115 to participate as a relay between base stations 105 and other user devices 115 (eg, out of coverage user device 115-a), the user devices 115 can participate in D2D discovery. D2D discovery timing may be governed by parameters passed to user devices 115 from a base station 105. These parameters and their use are explained in more detail below.

[00037] The communication links 125 shown in the wireless communication system 100 may include uplink transmissions (UL) from a user device 115 to a base station 105 or downlink transmissions (DL) from a base station 105 to a user device 115. Downlink transmissions may also be called link transmissions hereinafter while uplink transmissions may also be called reverse link transmissions.

[00038] Figure 2 is a block diagram of an example of a system 200 in which various embodiments can be implemented. The system 200 of Figure 2 can be an example of the wireless communication system 100 described with respect to Figure 1. In one configuration, the base station 105-a can communicate with one or more devices that are within a coverage area 110-a from the base station 105-a. A user device in coverage 115-b-1 may receive/transmit communications to/from base station 105-a. One or more user devices 115-b-2, 115-b-3, 115-b-4, 115-b-5 may fall outside the coverage area 110-a of the base station 105-a and can participate in D2D communications. Another user device 115-b-6 may be within coverage area 110-a of base station 105-a, but may also still participate in D2D communications. Base station 105-a and user devices 115-b can be examples of the base stations 105 and user devices 115 described with reference to figure 1.

[00039] In one embodiment, the user device in coverage 115-b-1 can transmit, multicast or unicast a peer discovery signal 205. The signal 205 can be sent to one or more user devices 115-b that are in or out of coverage. The peer 205 discovery signal may be a Long Term Evolution (LTE) peer discovery signal. In one embodiment, signal 205 may include an identifier of the user device in coverage 115-b-1. For example, the identifier may be a media access control (MAC) address of the user device in coverage 115 - b-1. Furthermore, the pair discovery signal 205 may include a user device 1 retransmission position 15-b-1. The relay position may indicate whether the user device in coverage 1 15-b-1 is capable of providing relay services to one or more user devices out of coverage 115-b.

[00040] In one example, an out-of-coverage 1 user device 15-b may receive peer discovery signals indicating that each one or more user devices in coverage 115-b is capable of functioning as a relay device. The out-of-coverage user device 115-b may then select one of the in-coverage user devices 115-b to provide relay services. The determination as to which user device in coverage 1 15-b to select may be based on a signal strength of the pair discovery signals received from each user device in coverage 115b, the IDs of the user devices in coverage 115 -b, or various other factors (for example, the remaining battery life of each user device in coverage 1 15-b (if running on batteries), the types of services supported by each user device in coverage 115-b ( if relay devices are selective about which services or applications they can or are willing to provide relay services), or the radio technologies for which each user device in 115-b coverage is willing to provide relay service. Some or all of these factors may be indicated or derived from peer discovery signals Some of the factors may also alternatively be obtained by querying the in-coverage user device 115-b from which the out-of-coverage user device 115-b received relay position and information of identifier.

[00041] In one embodiment, a user device out of coverage 115-b may transmit a peer discovery signal 205 to one or more user devices in coverage 115-b-l. The peer discovery signal may indicate that the out of range user device 115-b is out of coverage or querying for relay services. The signal may include an out of range user device identifier 115-b. In one embodiment, a user device 115-b may transmit a peer discovery signal 205 when it perceives that it is about to be outside the coverage area 110-a of the base station 105-a. In another embodiment, a user device 115-b may transmit signal 205 after it is already outside coverage area 110-a.

[00042] In one example, user devices outside of coverage 115-b-2, 115-b-3 can communicate with each other. For example, user devices 115-b-2, 115-b-3 can establish a direct D2D connection. The user device in coverage 115-b-1 may also provide relay services to one or more user devices out of coverage 115-b. In one embodiment, a first out-of-coverage user device 115-b-4 may serve as a relay device for a second out-of-coverage user device 115-b-5. The first out of coverage user device 115-b-4 may transmit a peer discovery signal 205 to inform the second out of coverage user device 115-b-5 that it (115-b-4) is capable of providing relay services. As another exemplary example, the second out-of-coverage user device 115-b-5 may transmit a signal 205 inquiring for relay services from the first out-of-coverage user device 115-b-4. As a result, the in-coverage user device 115-b-1 can relay communications to/from the base station 105-a from/to the first out-of-coverage user device 115-b-4. The first out-of-coverage user device 115-b-4 may transmit at least a portion of the communications from/to the second out-of-coverage user device 115-b-5.

[00043] As an additional example, two user devices in coverage 115-b-l, 115-b-6 can also communicate with each other via a direct D2D connection. In this example, user device 115-b-6 may transmit a signal 205 by querying a direct D2D connection with other user devices 115-b along with user device 115-b-6. User device 115-b-1 may receive a request and then initiate direct D2D communications with user device 115-b-6.

[00044] Before any of the D2D communication examples described above can occur, however, pair discovery signals 205 from receiving user devices 115 will be able to currently receive and decode the 205 signals. receiver 115 may need to know when to listen for the pair discovery signals 205. In a synchronous deployment, a synchronization issue can be simplified by using the common system synchronization transmission by the Base Stations 105. However, in asynchronous deployments, the Stations base 105 may not share a common system sync. Therefore, user devices 115 can either learn or receive synchronization from peer discovery signals sent from nearby user devices 115.

[00045] Additionally, a user device 115 seeking to receive a pair discovery signal 205 from another user device 115 may know which of the available time frequency resources are being used to transmit the pair discovery signal 205. Due to the fact that user devices 115 involved in D2D discovery at any point in time are equally likely to change, the discovery protocol used by user devices 115 may be operated periodically. User devices 115 may therefore have a need to know the periodicity of available discovery resources.

[00046] In order to facilitate this communication, the base stations 105 may transmit necessary parameters that will enable D2D discovery. The required parameters can be transmitted via a System Information Block (SIB) or a dedicated Radio Resource Control (RRC) message, for example. 3 is an example of a part of a SIB message 300 carrying one or more parameters used by user devices 115 to participate in D2D discovery. The SIB message 300 is an example of parameters that are transmitted between the base station 105 and a user device 115, as depicted in Figures 1 or 2. The SIB message 300 can be implemented in any of the existing SIB messages or it can be an entirely new SIB message. The example illustrated in Figure 3 shows that the SIB 300 message includes one or more discovery-related parameters. These include a discovery period parameter 305, an SFN length parameter 310, a discovery offset parameter 315, a discovery subframes parameter 320, an RB discovery length parameter 325, start and end point parameters RB of discovery 330, modulation and encoding parameters 335, a sync signal parameter position 340, a transmit power parameter 345, an authorized mode of operation parameter 350, a second common bitmap parameter 355, a parameter of transmission resource selection method 360, a DMRS usable cyclic changes parameter 365 as well as other parameters 370. Each of these parameters is explained in detail below. The SIB message 300 is not limited to supporting the specific parameters illustrated in FIG. 3, nor does the SIB message 300 need to include each of the illustrated parameters.

[00047] SIB message 300 may be used to transmit discovery related parameters from a base station 105 to one or more user devices 115. Parameters supported by SIB message 300 may alternatively be included in a dedicated RRC message which is transmitted from a base station 105 to one or more user devices 115.

[00048] Figure 4A is a message flowchart 400 illustrating an embodiment of communications between a base station 105-b and user devices 115-c-1 and 115-C-2 (herein collectively referred to as user devices 115-c) . Base station 105-b and user devices 115-c may be examples of the base stations 105 and user devices 115 depicted in FIGS. 1 or 2. Peer Discovery Parameter messages 405 and 410 may additionally be examples of the SIB message 300 described with respect to figure 3, as described above.

[00049] In one configuration, base station 105-b may transmit the required peer discovery parameters to user devices 115-c.

[00050] The base station 105-b transmits a discovery parameters message 405 to the user device 115-c-1. Discovery parameter messages 405 may be an example of SIB message 300 (of FIG. 3). Base station 105-b also transmits a discovery parameters message 410 to user device 115-C-2. Discovery parameters message 410 may also be an example of SIB message 300 (of Figure 3). Once user devices 115-c have received the pair discovery parameters, user devices 115-c are able to participate in D2D discovery.

[00051] As an example of D2D discovery, user devices 115-c-1, 115-C-2 can use the received pair discovery parameters to respectively select a discovery resource among the resources reserved for discovery. Alternatively, specific discovery resources may be dedicated to or assigned by base station 105-b to a specific user device 115. User devices 115-c-1, 115-C-2 respectively transmit a discovery signal to the selected or assigned discovery resource during each discovery period. User devices 115-c-1, 115-C-2 also listen for discovery signals from other user devices 115 on the remaining discovery resources. Once a user device 115 is discovered by another user device 115 (i.e., a discovery signal from user device 115 is received by a different user device 115), the receiving user device 115 can respond directly to the transmission user device 115 in order to establish a direct D2D communication. Therefore, in the example of Fig. 4A, user device 115-C-2 transmits a first pair discovery signal 415, which is received by user device 115-c-1. Once user device 1 15-c-l elects to participate in D2D communication with user device 115-C-2 (at block 420), user device 1 15-c-l transmits a response or second pair discovery signal. 425 to advertisement user device 115-C-2. By exchanging the first second pair discovery signals 415, 425, user devices 115-c-1, 115-C-2 can engage in direct D2D communication 430 with each other.

[00052] An example of the communications between user devices during D2D discovery is also illustrated in Figure 4B. As illustrated in Figure 4B, resources 450 may be allocated for D2D discovery as well as network communications. Thus, the resources 450 illustrated in Figure 4B can be examples of resources used during any of the communications between user devices 115 and Base Stations 105, as described with respect to Figures 1, 2, or 4A. These resources can be organized into a periodically available 455 discovery period. During a portion of the discovery period 455, discovery subframes 460-1, 460-2 may be allocated for use in D2D discovery. Other subframes 465-1, 465-2, 465-3 are reserved for non-discovery related communications such as wide area network (WAN) communications. Specific discovery subframes 460-1, 460-2 and their use may be specified by a discovery parameters message 405, 410 (as described with reference to FIG. 4A).

[00053] Figure 5 is an example of a block diagram 500 of an apparatus 505 for use in wireless communication, in accordance with various aspects of the present description. In some examples, apparatus 505 may sample aspects of one or more of the user devices 115 described with reference to Figures 1, 2, or 4A, and may receive D2D parameters as illustrated in SIB message 300 of Figure 3. Apparatus 505 may also be a processor. Apparatus 505 may include a receiver module 510, a peer discovery module 515, or a transmitter module 520. Each of these components may be in communication with each other.

[00054] The components of apparatus 505 may, individually or collectively, be implemented using one or more application-specific integrated circuits (ASICs) adapted to perform some or all of the applicable functions in hardware. Alternatively, the functions may be performed by one or more other processing units (or cores) on one or more integrated circuits. In other examples, other types of integrated circuits may be used (eg, Structured/Platform ASICs, Field Programmable Gate Arrays (FPGAs), and other Semi-Custom ICs), which may be programmed in any manner known in the prior art. The functions of each unit can also be implemented, in whole or in part, with instructions embodied in a memory, formatted to be executed by one or more processors of general application or specific application.

[00055] In some examples, receiver module 510 may include at least one radio frequency (RF) receiver such as at least one RF receiver operable to receive transmissions over a radio frequency spectrum. In some examples, the radio frequency spectrum may be used for LTE/LTE-A communications, as described, for example, with reference to Figure 2. Receiver module 510 may be used to receive various types of data or control signals. (i.e., transmissions) over one or more communication links of a wireless communication system, such as one or more communication links 125 of the wireless communication system 100 described with reference to Figure 1. Examples of the types of data or control signals received by receiver module 510 include the pair discovery signals 205, 415, 425, the SIB message 300 described with reference to FIG. 3, and the pair discovery parameter messages 405, 410 described with reference to the FIGS. 2 or 4A.

[00056] In some examples, transmitter module 520 may include at least one RF Transmitter, such as at least one RF transmitter operable to transmit discovery messages. Transmitter module 520 can be used to transmit various types of data or control signals (i.e., transmissions) over one or more communication links of a wireless communication system, such as one or more communication links 125 of the wireless communication system. 100 described with reference to Figure 1. Examples of the types of data or control signals transmitted by transmitter module 520 include the pair discovery signals 205, 415, 425 described with reference to Figures 2 or 4A.

[00057] In some examples, the peer discovery module 515 can be used to manage the receipt of peer discovery signals 205, 415, 425 (see figures 2 and 4A) via the receiver module 510 or to manage the transmission of peer discovery signals 205, 415, 425 (see FIGURES 2 or 4A) via transmitter module 520. Managing the reception and transmission of peer discovery signals may include receiving peer discovery parameter messages 405, 410 ( of Figure 4A) via the receiver module 510 and applying the received parameters to the process of receiving and transmitting pair discovery signals 205, 415, 425.

[00058] Figure 6 shows a block diagram 600 that includes apparatus 505 -a, which may be an example of one or more aspects of apparatus 505 (of Figure 5) for use in wireless communication, in accordance with various aspects of the present description. In some examples, apparatus 505-a may include a receiver module 510-a and a transmitter module 520-a, which are Examples of receiver module 510 and transmitter module 520 of Figure 5. In further examples, apparatus 505-a may include a peer discovery module 515-a, which may be an example of one or more aspects of the peer discovery module 515 of FIG. 5 . In some examples, the peer discovery module 515-a may include a module of discovery period 605, a discovery length module 610, a modulation, power and synchronization module 615 and an option and mode module 620. The modules 605, 610, 615, 620 are respectively for reception and various use parameters in the D2D discovery that may be received in one or more discovery parameter messages 405, 410 (of Fig. 4A) or in the SIB message 300 (of Fig. 3). Each of the modules 605, 610, 615, 620 may themselves include various sub-modules for receiving and using specific parameters, as described below.

[00059] An example of the discovery period module 605 is illustrated in Figure 7. Figure 7 shows a block diagram 700 of one or more examples of aspects of the discovery period module 605 (of Figure 6), according to various aspects of the present disclosure. In the example of Figure 7, the period discovery module 605 may include a period discovery submodule 705, a system frame number (SFN) extension submodule 710, a discovery offset submodule 715, and a discovery period submodule 715. discovery subframes 720.

[00060] The period discovery submodule 705 allows the apparatus 505 (such as a user device 115) to receive and process a period discovery parameter 305 (see Figure 3). The discovery period parameter 305 identifies a discovery period in which discovery resources are available for D2D discovery. Discovery period parameter 305 can be any value indicating a period of time. In one example, the discovery period parameter 305 is either a fraction (eg, 1/4, 1/2, etc.) or a multiple (eg, 1, 2, 3, etc.) of the maximum SFN of network. In an LTE configuration, the maximum SFN equals 10.24 seconds. Therefore, the discovery period parameter 305 can be a fraction or a multiple of 10.24 seconds.

[00061] The discovery period includes a plurality of subframes. Subframes within the discovery period can all be reserved for D2D discovery. However, to reduce any interference with the communication device unrelated to user discovery, some of the subframes within the discovery period may be reserved for other network communications. Thus, not all subframes within the discovery period are reserved as discovery subframes. In fact, discovery subframes within the discovery period cannot even be contiguous with each other. Thus, discovery period parameter 305 defines a time period that is long enough to include all available discovery resources, even if the resources/subframes are not contiguous.

[00062] The discovery period parameter 305 is defined by a base station which then allocates a pool of radio resources for discovery operations of the frequency defined by the discovery period. The base station also ensures that the subframes, in which the radio resources are allocated, are not available for physical uplink shared channel (PUSCH) transmissions. For user devices that are connected via the RRC, the base station ensures that any hybrid automatic retry and request (HARQ) operations that might fall back on the allocated discovery resources are suspended.

[00063] During the allotted discovery period, user devices either transmit or receive discovery signals. For example, an announcing user device (a user device that is transmitting a discovery signal) can select one of the radio resources from the allocated pool of radio resources and perform a discovery transmission. User devices then use the rest of the discovery subframe in the discovery period to monitor discovery signals from other user devices.

[00064] However, the user device can prioritize other events. For example, if an available discovery feature overlaps with paging, eg, etc., the monitoring user device may suspend discovery in order to receive a paging message from a base station. In contrast, RRC CO NECTED user devices may assume that any HARQ processes that overlap allocated discovery subframes have been suspended.

[00065] In one embodiment, multiple discovery periods may be established using discovery period parameter 305. Each discovery period may correspond to a user device class. Discovery classes can be provided to a user device based on, for example, subscription rights. As an example, the use of multiple discovery periods allows a base station to assign a higher discovery period frequency to a higher class user device so that the user device can be discovered in an accelerated manner. When there are multiple discovery periods, a monitoring user device can be configured to only be aware of certain discovery periods, based on, for example, the user device's subscription. Alternatively, a user monitoring device can be configured to monitor all available discovery periods. And in yet another embodiment, a monitoring user device can indicate to a user of the user device all available discovery periods, and thus allows the user to identify which of the available discovery periods should be monitored.

[00066] Multiple discovery periods can also be managed by configuring different user devices to be members of different numbered classes, where the class number represents a multiple of a transmission of base discovery period in e.g. a SIB message . In this way, user devices can implement different discovery periods based on the user device class, even if a single common SIB message having a single discovery period parameter 305 is transmitted. Some or all of the plurality of parameters may differ based on a user device class. For example, parameters can have different shapes, lengths, offsets, etc., based on a user device class.

[00067] In addition, discovery resources can be allocated for specific purposes. For example, in one embodiment, some discovery resources may be allocated for business purposes while other discovery resources are allocated for public safety purposes. Differently allocated resources may have different discovery periods. The discovery period parameter 305 supported in a SIB message 300, for example, may indicate that the discovery period is for a specific purpose.

[00068] The discovery period module 605 may also include an SFN extension submodule 710. The SFN extension submodule 710 may be used when the discovery period indicated by the discovery period parameter is longer than the maximum SFN. As an example, when the discovery period is a multiple of a maximum SFN, the SFN extension submodule 710 receives an SFN extension parameter 310 that indicates a number of times the maximum SFN is exceeded during the discovery period. The SFN extension parameter 310 can be, for example, a counter reporting how many times SFN loop reset has occurred during a single discovery period. With the use of the SFN extension parameter 310, the discovery resource pool can be allocated even multiple times within a discovery period that are in excess of the maximum SFN. The SFN extension parameter 310 is incremented by one SFN reset at a time within the same discovery period. Once the discovery period is exceeded, meaning once a maximum extended SFN has been reached, where the maximum extended SFN is equal to the discovery period as an integer multiple of 10.24 seconds, the SFN extension parameter 310 also resets cyclically.

[00069] In case multiple discovery periods are identified within, for example, the SIB message, the maximum extended SFN can be set to be the maximum or longest discovery period. When the value of the SFN extension parameter 310 is being changed regularly but does not necessarily represent a change in system information, the systemlnfoModification RC message or systemlnfoModification paging message (on an LTE system) may not be updated after incrementing the SFN extension parameter 310.

[00070] Both annunciators and monitoring user devices keep track of the SFN extension parameter 310. User devices can do this by checking the value every time, for example, a SIB message is transmitted. Alternatively, user devices can store the SFN 310 extension parameter as a local variable after the parameter has first acquired a SIB message, for example. If stored as a local variable, user devices handle incrementing the SFN extension parameter 310 every time the maximum SFN is exceeded. Likewise, user devices handle the cyclic restart of the SFN extension parameter 310 every time the maximum discovery or extended SFN period is exceeded.

[00071] The discovery period module 605-a may also include a discovery offset submodule 715. The discovery offset submodule 715 receives a discovery offset parameter 315, which indicates any offset between the start of the discovery period and a reference point based on the fixed time. As an example, a fixed time-based reference point might be when SFN equals zero and any SFN extension also equals zero. Both monitoring and advertising user devices receive the discovery offset parameter 315 and add its value to the known reference point in order to calculate the discovery resource pool starting point.

[00072] In case multiple discovery periods are indicated by discovery period parameter 305, discovery offset parameter 315 will also indicate different corresponding offset values. For example, when the discovery period parameter 305 indicates different discovery periods based on the class type (eg commercial class, public safety class, etc.) of the user devices, then the user devices will apply the offset that matches your class type. The discovery offset parameter can also indicate an offset between the start of the discovery period and a fixed time-based reference point for both transmit and receive groups. In some examples, a neighbor receiving group offset may also be indicated with respect to the fixed reference point of a serving cell.

[00073] The discovery period module 605-a may also include a discovery subframe submodule 720. Although allocated discovery subframes are available throughout the discovery period, the available discovery subframes also cannot be contiguous. Discovery subframes within a discovery period can be divided into groupings so that the user device does not neglect non-discovery activities for too long a period. In other words, non-discovery subframes can be interspersed with discovery subframes. However, the discovery subframes submodule 720 may receive a discovery subframes parameter 320 that indicates which subframes within the discovery period are available as discovery resources. The discovery subframes parameter 320 may be a bitmap, which indicates which subframes have been allocated for discovery purposes and which subframes have been allocated for non-discovery purposes (e.g., for wide area network (WAN) purposes). .

[00074] The bitmap of discovery subframes can indicate the starting point of where discovery resources start each discovery period. As an example, in the bitmap, bits can be set to I ) if a corresponding subframe is allocated for discovery. Otherwise, bits are set to '0' if the corresponding subframe is allocated for eg WAN operation.

[00075] Monitoring and advertising user devices use discovery subframes parameter bitmap 320 to identify available discovery subframes. In the event that multiple discovery periods are present for different class or type (e.g., commercial safety or public safety classes), discovery subframes parameter 320 may include a single bitmap applicable for all discovery periods or the discovery subframes parameter 320 may include multiple different bitmaps for different discovery periods.

[00076] Alternatively, the discovery subframes parameter 320 does not need to be a bitmap. Instead, discovery subframes parameter 320 may be a series of values indicating successive lengths of contiguous discovery subframes and lengths of gaps between discovery subframes. Thus, the discovery subframes parameter 320 fully represents the available discovery subframes as well as the available subframes available for WAN operations. Alternatively, discovery subframes parameter 320 may represent subframes corresponding to certain HARQ processes reserved for each discovery operation discovery period.

[00077] In addition to the discovery period module 605, the pair discovery module 515 also includes a discovery length module 610, modulation, power and synchronization module 615 and an options and modes module 620, as illustrated in Fig. 6 . Discovery length 610 is capable of receiving and using various discovery parameters, either directly or through various submodules.

[00078] A parameter received through the discovery length module 610, for example, is the RB discovery length parameter 325. The RB discovery length parameter 325 indicates a number of RBs to be used for each discovery signal within of a subframe available as a discovery feature. The discovery RB length parameter 325 can be a single value, where all available discovery subframes include that given number of discovery RBs.

[00079] Alternatively, the RB discovery length parameter 325 can be multiple values, each value representing a length or number of RBs available within each division of a subframe.

[00080] In addition, the RB discovery length parameter 325 can also indicate different RB lengths for different classes or types of user devices.

[00081] User Announcement Devices use the discovery length parameter RB 325 in order to find appropriate discovery resources available for transmitting a discovery signal. In contrast, user monitoring devices use the discovery length parameter RB 325 to define the size required at the physical layer in order to perform decoding operations.

[00082] Additional parameters received through discovery length module 610 include discovery RB start and end point parameters 330. These parameters are used with RB discovery length parameter 325 to allow determination of where in each division the allocated games of RBs both start and stop. This can be important when pre-existing WAN operations override a discovery feature so that PUCCH transmissions may still be in use.

[00083] In use, user annunciator devices use the received starting point along with the discovery length parameter RB 325 to find an appropriate discovery resource for transmission of the discovery signal. This can be done, for example, using a sliding window of length equal to the discovery length parameter value RB 325 and starting from the received start point and ending at the received end point. The resource framed by the sliding window can then be analyzed to determine if it is appropriate (for example, the energy level of the resource can be measured and compared). This can be repeated until a discovery resource is found. Meanwhile, monitoring user devices will use discovery RB start and end point parameters 330 to determine when to start decoding discovery signals. Decoding continues from the discovery start point, in steps of length equal to the value of discovery length parameter RB 325, until the discovery end point is reached in each discovery subframe.

[00084] The modulation, power and synchronization module 615 can also receive various discovery parameters, either directly or through sub-modules. A set of parameters received at modulation, power and sync module 615 are modulation and encoding parameters 335. Modulation and encoding parameters 335 indicate a modulation and encoding scheme for transmission of discovery signal. These parameters may be common to all types of user devices, or may alternatively be different for different types of user device classes. While user announcing devices use this parameter to establish modulation and encoding schemes, monitoring user devices use this parameter to instruct respective physical layers to perform appropriate decoding operations.

[00085] Another parameter received in the modulation, power and synchronization module 615 is the position of synchronization signal parameter 340. Base stations transmit synchronization signals. When a user device changes from the coverage area of a first base station and into the coverage area of a different base station, the user device must acquire the synchronization signal from the different base station. To facilitate this, user devices in coverage of a first base station can forward that base station sync signal to user devices in coverage of other base stations, thus allowing all user devices to more easily synchronize to the first base station. base. However, the radio resources used to transmit from a user device, a base station synchronization signal may vary as established by the Base Stations. Therefore, the location of these sync signals, as forwarded by user devices, can be indicated by receiving sync signal parameter position 340.

[00086] An example of when the sync signal parameter 340 is particularly useful is when a user device is very close to its base station. If, for example, a first user device is within the discovery range of another user device, but the first user device is too close to its own base station, the first user device may not be able to decode the synchronization signal transmitted by the base station of the second user device. For that matter, the other user device - the one participating in discovery with the first user device - can retransmit the synchronization signal from its associated base station. The synchronization signal can be retransmitted for example in the first subframe of the allocation to the respective other user device macro. The retransmitted sync signal can be the same as a primary/secondary sync signal (PSS/SSS) transmitted by the other user device macro. The retransmitted synchronization signal can also be PSS repeated. To increase the strength of the retransmitted sync signal, all user devices associated with the macro will transmit at the same time and frequency resource. In this way, the power coming from different user devices sums up at the reception of the first user device. To reduce the possibility of overlap between the sync signal and the discovery signals of another macro not close to user devices that have largely overlapping allocation, the time and frequency feature can be located in the first few symbols of the first subframe. Additionally, the frequency at which the sync signal is transmitted can be different for non-close macros that have largely overlapping allocations. This allows a user device receiving the sync signal to distinguish between the sync signals of different macros. The retransmission of synchronization signals by user devices can be controlled by the respective base stations. For example, different base stations can instruct user devices to transmit synchronization signals with different frequency. Additionally, transmission of synchronization signals can be limited to only a certain class of user devices. Alternatively, user devices can be randomly selected for transmission of the sync signal.

[00087] As mentioned above, however, the positions of these synchronization signals may be different for different Base Stations. Thus, the position of sync signal parameter 340 can indicate a signal position for a neighboring base station. This allows a monitoring user device, for example, to know how to receive a specific synchronization signal from the neighboring base station when it is retransmitted by other user devices.

[00088] Another parameter received in the modulation, power and synchronization module 615 is the transmit power parameter 345. As needed, discovery operations may need to be limited in the power used. Correspondingly, transmit power parameter 345 can be received and indicates a power level for transmitting discovery signal. If the transmit power parameter 345 is missing, a user device can use its maximum power for discovery operations. Otherwise, the user device will be power limited based on the parameter value.

[00089] In one embodiment, all allocated discovery resources can be divided into different transmit power zones. In this case of multiple power zones, the transmit power parameter 345 will indicate, in addition to a transmit power value for each zone, a start and end point defining each zone. Thus, transmit power parameter 345 is used by user annunciator devices to transmit discovery signals at designated power levels on selected or assigned discovery resources.

[00090] As an example, discovery resources can be divided into lower power zones or higher power zones. Low power and high power resources can respectively be frequency domain multiplexing (FDM) or time domain multiplexing (TDM). When the power zones are FDM, the transmit power parameter 345 can be a bitmap representing commonly allocated subframes for discovery, with the start and end points of both low and high power resources being indicated. Alternatively, start and end points for power zones can be indicated in the form of a starting position RB and an RB length for a low power and high power resource. The remainder of the resources in that subframe are reserved for the other remaining power level. User annunciator devices can then use the transmit power parameter to perform a calculation to find low power and high power resources in a discovery subframe. Monitoring user devices can, if desired, monitor both low power and high power resources. However, in another embodiment, monitoring user devices may also perform computations to locate a low-power and high-power resource pool in a discovery subframe if the user device is a member of a class that is only authorized to monitor one of two low power or high power resources.

[00091] When low power and high power resources are TDM, then the transmit power parameter can be two separate bitmaps: one indicating discovery subframes for low power and one for discovery subframes for high power. In one embodiment, a common offset from a reference point may indicate the starting position of the discovery subframe bitmap. So, in this situation, one resource pool starts at the indicated offset while the other resource pool starts at the offset plus the bitmap length of the starting resource. In contrast, and in a different embodiment, the power transmission parameter may include separate offsets from a reference point for low power and high power. In yet another embodiment, low power and high power resources may be subframe interleaved and may exhibit the same offset from a common reference point. Even so, each of the interleaved bitmaps need not be the same length, but could also be different lengths. In this embodiment, user devices combine bitmaps to identify all discovery subframes as well as WAN operation subframes. In yet another embodiment, the length of the bis maps can also be indicated.

[00092] When low power and high power resources are TDM, the user annunciator device utilizes low power or high power zones as needed by the base station serving the user device. In contrast, monitoring user devices can monitor both low power and high power resources. However, in some embodiments, the monitoring user devices are class-restricted to monitoring only one type of power resource. In yet another embodiment, different power zones can have different periodicity. For example, the combination of a low power maximum zone, using only a small number of subframes, and having a fast duty cycle can be beneficial for short range discovery.

[00093] The options and modes module 620 (figure 6) can receive even more discovery parameters. A parameter received either by the 620 options and modes module or by submodules within the 620 options and modes module is the 350 operating parameter mode. The 350 operating parameter mode indicates whether discovery can occur when the user device is in a connected mode or in an idle mode, or both. These modes are commonly referred to as an RRC Connected Mode or an RRC Idle Mode. Additionally, it is possible that transmission of discovery signals and reception of discovery signals may have different authorized mode configurations. Thus, authorized mode of operation parameter 350 indicates any settings that are contingent on the desired discovery activity. Therefore, the parameter mode of operation could be the same, but could also be different for both annunciator user devices and monitoring user devices. Naturally, user devices are allowed to transition to an authorized state before partitioning on discovery. Also, the parameter mode of operation may vary based on a user device class.

[00094] Another parameter received by either the options and modes module 620 or sub-modules within the options and modes module 620 is the dedicated or common discovery resource pool parameter. This parameter indicates whether discovery features are common to user devices or whether specific discovery features are dedicated to specific user devices. Depending on the network configuration, certain user devices perform broadcast discovery in a common discovery pool by autonomously selecting a radio discovery resource from the available discovery resources. In contrast, other user devices can be dedicated resources assigned for discovery signal transmission.

[00095] Common and dedicated resources can be FDM or TDM. In case the resources are FDM, the common or dedicated discovery resource pool parameter may be commonly accessed bitmap representing subframes allocated for discovery, and start and end points of both common or dedicated discovery resources will be indicated. Start and end points can be indicated in the form of a starting position of an RB length and a common or dedicated resource RB. The remainder of the resources in that subframe are reserved for the other remaining type (either common or dedicated). User annunciator devices can then use the dedicated or common discovery resource pool parameter to perform a calculation to find the common and dedicated resources in a discovery subframe. Monitoring User Devices can, if desired, monitor as many Common Resources as Dedicated Resources. However, in another embodiment, monitoring user devices may also perform calculations to locate a specific common or dedicated resource pool in a discovery subframe if the user device is a member of a class that is only authorized to monitor one of the two. common or dedicated resources.

[00096] When common and dedicated resources are TDM, separate bitmaps for common discovery subframes and dedicated discovery subframes can be used for dedicated or common discovery resource pool parameter. In one embodiment, a common offset from a reference point can indicate the starting position of the discovery subframe bitmap. So, in this situation, one resource pool starts at the indicated offset while the other resource pool starts at the offset plus the length of the starting bitmap resource. In contrast, in another embodiment, the dedicated or common discovery resource pool parameter may include separate offsets from a reference point for common and dedicated resources. In yet another embodiment, common or dedicated resource bitmaps may be subframe interleaved and may display the same offset from a common reference point. Even so, each of the interleaved bitmaps need not be the same length, but could also be different lengths. In this embodiment, user devices combine both bitmaps to identify all discovery subframes as well as all WAN operation subframes. In yet another embodiment, the length of the bitmap can also be indicated.

[00097] When common and dedicated resources are TDM, the user annunciator device utilizes the common or dedicated resources as needed by the user device base station. In contrast, monitoring user devices can monitor both common and dedicated resources. However, in some embodiments, monitoring user devices are restricted by class to only monitoring one type of resource. In yet another embodiment, different types of resource may have different periodicity.

[00098] Another parameter received either by the options and modes module 620 or by sub-modules within the options and modes module 620 is the transmission feature selection method parameter 360. This parameter 360 indicates a method to be used by a user device to select which of the available discovery resources should be used for discovery signal transmission. For example, resource selection method parameter 360 could indicate that a user device should be randomly selected from the available discovery resources for the user device (in accordance with all other parameters received by the user device). Alternatively, this parameter 360 could instruct a user device to select discovery resources based on energy levels of available resources. For example, if the user device detects that energy levels for a certain resource exceed a threshold, then the user device may elect not to use that resource, but instead use resources that have lower energy levels. As a third alternative, the broadcast resource selection method parameter 360 may indicate that a user device should select resources in order to group resources.

[00099] Yet another parameter received either by the options and modes module 620 or by sub-modules within the options and modes module 620 is the reference signal usable cyclic changes for demodulation (DMRS) parameter. This parameter indicates which DMRS Cyclic Shifts are available and the DMRS shift timing pattern.

[000100] Additional parameters that can be received by the user device via, for example, the options and modes module 620, include a system time parameter and parameters related to the duration that dedicated resources can be assigned. These parameters can be received under the category of other parameters 370 (with reference to SIB message 300 of Fig. 3). A system time parameter indicates a system, or wall clock time, that is the same for all user devices. The system time parameter provides a system time which can then be used in conjunction with a security key to perform hashing (splitting) operations on the discovery messages to be transmitted. The system time parameter could be used as transmitted from SIB 16 or could alternatively be used as a parameter in a new SIB discovery message. As an alternative to using system time for hashing, SFN or extended SFN can be used if the network is synchronous. As another alternative, a shared countervalue, shared between neighboring base stations, could be used in place of system time (for operation hashings). As the value of the system time parameter changes regularly but does not necessarily represent a change in system information, the system information modification paging message or the system information value marking message (in an LTE system) may not be updated after incrementing the system time parameter.

[000101] Since the second bitmap can only be dedicated for a period of time (for example, a number of discovery periods, or a number of discovery transmissions), this number or limitation on the period of a discovery resource Assigned dedicated can also be included as a discovery parameter received by user devices. Similarly, user devices can also receive as a discovery parameter a limitation on the number of empty discovery transmissions that can occur before a user device can assume that dedicated resources used for the transmissions have been reallocated.

[000102] All or some parameters described above can be transmitted to user devices from their respective base stations, where the received parameters refer specifically to the base stations corresponding to the user device. However, the base station can also transmit all or some of the parameters described above as they belong to neighboring base stations. Transmission parameters belonging to neighboring Base Stations can also be transmitted, for example, to a discovery message SIB 300 (see FIGURE 3). While each of the parameters belonging to a neighboring base station can be transmitted, some of the more relevant parameters in some examples may include the discovery period and SFN extension parameters 305, 310, the discovery subframes parameter 320, the discovery parameter discovery offset 315, the discovery length parameter RB 325, the start and end point parameters RB discovery 330, and the position of sync signal parameter 340. In the vast majority of cases, if any of the parameters are missing for a neighboring base station, a user device may attempt to use the parameters for the base station currently serving the user device. Specifically, while the position of synchronizing signal parameter 340 for a neighboring base station must be provided, the absence of any of the other parameters for a neighboring base station may simply mean that the values for the neighboring base station and the current base station are the same.

[000103] All or some of the parameters described above can also be provided for each frequency and/or for each network (such as a public land mobile network (PLMN)) in the vicinity. It is possible that multiple carrier networks may share a carrier frequency for discovery, or there may be carrier aggregation in which a primary base station transmits discovery information regarding the secondary base station. In this case, the SIB discovery message will also carry information related to the frequency where the discovery is performed.

[000104] When the SIB discovery message format is updated, all user devices may need to be informed that an update is required. Correspondingly, base stations may transmit (as part of, for example, a SIB message or a paging message) an instruction that user devices may reset and update. For example, updates may need to occur when a user announcer device wants to get a D2D expression code from a base station, and a monitoring user device wants to get a D2D filter in order to monitor one or more user devices. . There may even be times when a base station wants all user devices to receive updated expression codes or filter codes. As an example, the base station may receive an instruction for all connected user devices to update from a Mobility Management Entity (MME) (which may have received the instruction via a ProSe instruction). Once the base station receives the instruction, the base station may transmit (as part of, for example, a SIB message or a paging message) the instruction that user devices may reset and update. As another example, when a SIB message (e.g., SIB message 300) is changed and this change must be indicated to user devices participating in D2D discovery, a base station can send a page message indicating that there is a change in the SIB message. The page message may contain an indication that there is a change in the SIB message used for D2D discovery. That way, only those user devices that are participating in D2D discovery will need to update the SIB message. Other user devices that do not participate in D2D discovery can ignore the update request.

[000105] Figure 8 shows a block diagram 800 of a user device 815 for use in wireless communication, in accordance with various aspects of the present description. User device 815 can be in a variety of configurations and can include or form part of a personal computer (e.g., a laptop computer, netbook computer, tablet switcher, etc.), a cell phone, a PDA, a digital video recorder ( DVR), an internet device, a game console, an e-book reader, etc. User device 815 may, in some instances, have an internal power supply, such as a small battery, to facilitate mobile operation. In some examples, user device 815 may be an example of one or more aspects of one of the user devices 115 or apparatus 505 described with reference to figures 1, 2, 4A, 5, or 6. User device 815 may be configured to implement at least some of the features and functions described with reference to figures 1, 2, 3, 4A, 5, 6, or 7.

[000106] The user device 815 may include a processor module 805, a memory module 810, at least one transceiver module (represented by a transceiver module (s) 830), at least one antenna (represented by antenna (s) 835), or a peer discovery module 515-b. Each of these components can communicate with each other directly or indirectly over one or more 825 buses.

[000107] Memory module 810 may include random access memory (RAM) or read-only memory (ROM). Memory module 810 can store computer-readable, computer-executable (SW) software code 820 containing instructions that are configured, when executed, to cause processor module 805 to perform various functions described herein, for communication, for example, discovery-related messages. Alternatively, software code 820 may not be directly executable by processor module 805 but be configured to cause user device 815 (eg, when compiled and executed) to perform various of the functions described herein.

[000108] The processor module 805 may include an intelligent hardware device, for example, a CPU, a microcontroller, an ASIC, and the like. Processor module 805 can process information received by transceiver modules 830 or information to be sent to transceiver modules 830 for transmission through antennas 835. Processor module 805 can handle, individually or in connection with pair discovery module 515- b, various aspects of receiving and managing discovery parameters. [0122] The transceiver modules 830 may include a modem configured to modulate packets and provide the modulated packets to the antennas 835 for transmission, and demodulate packets received from the antennas 835. The transceiver modules 830 may, in some examples, be implemented as one or more transmitter modules and one or more separate receiver modules. Transceiver modules 830 may support discovery related communications. Transceiver modules 830 may be configured to communicate bidirectionally, via antennas 835, with one or more of the Base Stations 105 described with reference to Figures 1 or 2. While user device 815 may include a single antenna 835, there may be examples in which user device 815 may include multiple antennas 835.

[000109] The peer discovery module 515-b can be configured to perform or control some or all of the features or functions described with reference to figures 1, 2, 3, 4A, 5, 6, or 7 related to D2D discovery. For example, peer discovery module 515-b can be configured to support receiving and managing some or all of the discovery parameters described above and identified, for example, in a SIB discovery message 300 (As illustrated in Figure 3) . In some examples, and by way of example, the peer discovery module 515-b may be an example of one or more aspects of the peer discovery module 515 described with reference to FIGS. 5, 6 or 7. The discovery module of pair 515-b may include a discovery period module 605-a (which may be an example of a discovery period module 605 of Figs. 6 or 7), a discovery length module 610-a (which may be an example of a discovery length module 610 of figure 6), a modulation, power and synchronization module 615-a (which may be an example of a modulation, power and synchronization module 615 of figure 6), and an options and modes module 620-a (which may be an example of the options and modes module 620 of FIG. 6 ). Peer discovery module 515-b, or portions thereof, may include a processor, or some or all of the functions of peer discovery module 515-b may be performed by processor module 805 or in connection with the processor module. 805.

[000110] Figure 9 is an example of a block diagram 900 of an apparatus 905 for use in wireless communication, in accordance with various aspects of the present description. In some examples, apparatus 905 may be exemplary aspects of one or more of the Base Stations 105 described with reference to Figures 1, 2, or 4A. Apparatus 905 may also be a processor. Apparatus 905 may include a discovery parameter assignment module 910 and/or a transmitter module 915. Each of these components may be in communication with each other. The components of apparatus 905 may, individually or collectively, be implemented using one or more ASICs adapted to perform some or all of the applicable functions in hardware. Alternatively, the functions may be performed by one or more other processing units (or cores) on one or more integrated circuits. In other examples, other types of integrated circuits may be used (eg, Structured/Platform ASICs, FPGAs, and other Semi-Custom ICs), which may be programmed in a manner known in the prior art. The functions of each unit can also be implemented, in whole or in part, with instructions embodied in a memory, formatted to be executed by one or more processors of general application or specific application.

[000111] In some examples, transmitter module 915 may include at least one RF Transmitter, such as at least one RF Transmitter operable to transmit at least the discovery parameters identified above. Transmitter module 915 can be used to transmit various types of data or control signals (i.e., transmissions) over one or more communication links of a wireless communication system, such as one or more communication links 125 of the wireless communication system. 100 described with reference to FIGURE 1. Examples of the types of data or control signals transmitted by transmitter module 915 include the peer discovery parameter messages 405, 410 described with reference to FIGS. Discovery Parameter Assignment Module 910 may be used to manage the transmission of Peer Discovery Parameters messages 405, 410 (see FIGURE 4A) via Transmitter Module 915. Peer Discovery Parameter Management Messages 405, 410 can include discovery message populating SIBs, for example, or dedicated RC messages. Figure 10 shows a block diagram 1000 of one or more exemplary aspects of an apparatus 905-a for use in wireless communication in accordance with various aspects of the present description. Apparatus 905-a may be an exemplary apparatus 905 as depicted in Figure 9 . Apparatus 905-a may include both discovery parameter assignment module 910-a and transmitter module 915-a. Apparatus 905-a may also include a receiver module 1005.

[000112] The components of the apparatus 905-a may, individually or collectively, be implemented using one or more ASICs adapted to perform some or all of the applicable functions in hardware. Alternatively, the functions may be performed by one or more other processing units (or cores) on one or more integrated circuits. In other examples, other types of integrated circuits can be used (for example, Structured/Platform ASICs, FPGAs, and other Semi-Custom ICs), which can be programmed in any way in the prior art. The functions of each unit can also be implemented, in whole or in part, with instructions embodied in a memory, formatted to be executed by one or more processors of general application or specific application.

[000113] In some examples, transmitter module 915-a may include at least one RF transmitter, such as at least one RF transmitter operable to transmit at least the discovery parameters identified above. Transmitter module 915-a may be an example of the transmitter module 915 described with reference to Figure 9. Transmitter module 915-a may be used to transmit various types of data or control signals (i.e., transmissions) over one or more links. communication links of a wireless communication system, such as one or more communication links 125 of the wireless communication system 100 described with reference to FIG. 1. Examples of the types of data or control signals transmitted by the transmitter module 915 include messages of pair discovery parameters 405, 410 described with reference to figures 2 or 4A.

[000114] In some examples, the receiver module 1005 may include at least one RF receiver, such as at least one RF receiver operable to receive wireless communication from user devices 115 and appliances 505 described with reference to figures 1 , 2, 4A, 5, 6, 7, 8, or 9.

[000115] In some examples, the discovery parameter assignment module 910-a can be used to manage the transmission of peer discovery parameter messages 405, 410 (see FIGURE 4A) via the transmitter module 915. discovery parameter assignment module 910-a may be an example of the discovery parameter assignment module 910 described with respect to FIG. 9 . Discovery parameter assignment module 910-a may, for example, populate message SIBs or RRC messages dedicated to discovery. In some examples, the discovery parameter assignment module 910-a populates the SIB messages or dedicated RRC discovery messages by assigning or inserting one or more of the above-described discovery parameters into the SIB discovery message or dedicated RRC discovery message. .

[000116] For example, discovery parameter assignment module 910-a may include multiple modules that determine or populate discovery parameters. A discovery period assignment module 1010 may be used to determine or populate the discovery period parameter 305, the SFN length parameter 310, the discovery offset parameter 315, and the discovery subframes parameter 320, such as these parameters are described above. An allocation module RB 1015 may be used to determine or populate the discovery length parameter RB 325 and the start and end point parameters RB discovery 330. A modulation, power and synchronization module 1020 may be used to determine or populate a modulation and encoding parameter, the sync signal parameter position 340, and the transmit power parameter 345. An options and mode module 1025 may be used to determine or populate the authorized mode of operation parameter 350, the second parameter or common bitmap 355, the transmission resource selection method parameter 360, and the DMRS usable cyclic changes parameter 365. Operations on any of the parameters by the discovery parameter assignment module 910-a may occur within of various modules and sub-modules and are not limited by the examples illustrated in FIG. 10. In addition, additional parameters may be generated or populated by Discovery Parameter Assignment module 910-a, such as the system time parameter and the parameters related to the duration of those dedicated resources can be assigned.

[000117] Figure 11 is a flowchart illustrating an example of a method 1100 for wireless communication, in accordance with various aspects of the present description. For purposes of clarity, method 1100 is described below with reference to aspects of one or more of the user devices 115 described with reference to FIGS. 1, 2, 4A, or 8, or aspects of one or more of the devices 505 described with reference to FIGS. 5, 6, or 7. In some examples, a user device such as one of user devices 115 or an apparatus such as one of apparatus 505 may execute one or more sets of codes to control functional elements of the device. user or device to perform the functions described below. In block 1105, method 1100 may include receive parameters for D2D discovery. Received parameters may include a 305 discovery period parameter, as described above. Received parameters can also include any one or more of the other discovery parameters described above. Namely, the received parameters may include any one or more of the following: a discovery period parameter 305, an SFN length parameter 310, a discovery offset parameter 315, a discovery subframes parameter 320, a length discovery RB 325, a discovery RB start and endpoint parameter 330, a modulation and encoding parameter 335, a position sync signal parameter 340, a transmit power parameter 345, an authorized mode of operation parameter 350 , a common or second bitmap parameter 355, a transmission resource selection method parameter 360, a DMRS usable cyclic changes parameter 365, a system time parameter, and parameters relating to the duration of those dedicated resources may be assigned . Other discovery-related parameters can be received as well.

[000118] In block 1110, method 1100 may include using received parameters to participate in D2D discovery. Received parameters can be used for example for user device in order to use discovery features.

[000119] In some embodiments, operations in blocks 1105 or 1110 can be performed using the peer discovery module 515 described with reference to figures 5, 6, 7, or 8.

[000120] Therefore, method 1100 can be used for wireless communication. Note that method 1100 is exactly one implementation and that the operations of method 1100 may be rearranged or otherwise modified so that other implementations are possible.

[000121] Figure 12 is a flowchart illustrating an example of a method 1200 for wireless communication, in accordance with various aspects of the present description. For purposes of clarity, method 1200 is described below with reference to aspects of one or more of the user devices 115 described with reference to Figures 1, 2, 4A, or 8, or aspects of one or more of the devices 505 described with reference to Figures 1, 2, 4A, or 8. 5, 6, or 7. In some examples, a user device such as one of user devices 115 or an apparatus such as one of apparatus 505 may execute one or more sets of codes to control functional elements of the device. user or device to perform the functions described below.

[000122] In block 1205, method 1200 may include receiving a discovery period parameter 305. The discovery period parameter 305 received identifies a discovery period in which discovery resources are available for D2D discovery. Received discovery period parameter 305 may also identify multiple discovery periods available for D2D discovery.

[000123] In block 1210, if a received discovery period is a multiple of SFN, then method 1200 may receive, in block 1215, an SFN length parameter 310. The SFN length parameter 310 may indicate a number of times that the maximum SFN is exceeded during the received discovery period. If the received discovery period is not a multiple of SFN, then method 1200 may not require any reception of an SFN extension parameter 310.

[000124] In block 1220, method 1200 may include receiving a discovery offset parameter 315. Discovery offset parameter 315 may indicate an offset between a start of the discovery period and a fixed time-based reference point. As an example, the fixed time-based reference point can be when SFN and any extended SFN both equal zero. In some examples, the discovery offset parameter may indicate an offset between the start of the discovery period and the fixed time-based reference point for both the transmit and receive groups. In some examples, a neighbor receiving group offset may also be indicated with respect to a fixed reference point of a serving cell of the user device or apparatus. At block 1225, method 1200 may include receiving a discovery parameter subframe. The discovery parameter subframe can indicate which subframes within the discovery period are available as discovery resources. The discovery parameter subframe can be in the form of one or more bitmaps.

[000125] In block 1230, method 1200 may include receiving an RB discovery length parameter 325. The RB discovery length parameter 325 may indicate a number of RBs to be used for each discovery signal within an available subframe as a discovery feature.

[000126] In block 1235, method 1200 may include reception of discovery RB start and end point parameters 330. Discovery RB start and end point parameters 330 are used with discovery RB length parameters 325 to indicate a start point and end point of one or more resource blocks to be used for each discovery signal within a subframe available as a discovery resource.

[000127] In block 1240, method 1200 may include using any one or more of the received parameters to participate in D2D discovery. Received parameters can be used for example for a user device in order to use discovery features. Although method 1200 can be performed as illustrated in Fig. 12, the receiving order and types of parameters need not be limited to the specific receiving order and types of parameters identified in Fig. 12. In other words, blocks 1205-1235 can occur in different orders and not all of the parameters indicated by these blocks can be received before the use of one or more of the parameters received in block 1240 takes place.

[000128] In some embodiments, operations in blocks 1205, 1210, 1215, 1220, 1225, 1230, 1235, or 1240 can be performed using pair discovery module 515 described with reference to figures 5, 6, 7, or 8 .

[000129] Therefore, method 1200 can be used for wireless communication. Note that method 1200 is exactly one implementation and that the operations of method 1200 may be rearranged or otherwise modified so that other implementations are possible.

[000130] Figure 13 is a flowchart illustrating an example of a method 1300 for wireless communication, in accordance with various aspects of the present description. For clarity, method 1300 is described below with reference to aspects of one or more of the user devices 115 described with reference to Figures 1, 2, 4A, or 8, or aspects of one or more of the devices 505 described with reference 5, 6, or 7. In some examples, a user device such as one of user devices 115 or an apparatus such as one of apparatus 505 may execute one or more sets of code to control functional elements of the device. user or device to perform the functions described below. At block 1305, method 1300 may include receiving a discovery period parameter 305. The received discovery period parameter 305 identifies a discovery period in which discovery resources are available for D2D discovery. Received discovery period parameter 305 may also identify multiple discovery periods available for D2D discovery. At block 1310, method 1300 may include modulation and encoding receive parameters 335. Modulation and encoding parameters 335 may indicate a modulation and encoding scheme for transmission of discovery signal.

[000131] In block 1315, method 1300 may include receiving a sync signal parameter position 340. The sync signal parameter position 340 may indicate a position of a sync signal from a neighboring base station when when that synchronization signal is forwarded by neighboring base station user devices. Thus, the sync signal parameter 340 allows a user device to receive the sync signal when it is forwarded by another user device. [0152] At block 1320, method 1300 may include receiving a transmit power parameter 345. Transmit power parameter 345 may indicate a power level for transmitting discovery signal. The discovery resources available can be divided into different power zones. When this is the case, transmit power parameter 345 can be used to indicate in which power zone a specific discovery resource is located. Transmit power parameter 345 may be in the form of a bitmap.

[000132] In block 1325, method 1300 may include reception of an authorized mode of operation parameter 350. Authorized mode of operation parameter 350 may indicate whether discovery may occur during a connected mode or during an idle mode of the device. user. At block 1330, method 1300 may include receiving a second or common parameter from bitmap pool 355. The available discovery resources may be either common or may be dedicated for the use of a specific user device. The common resource pool parameter or second bitmap pool parameter can indicate whether available discovery resources are either common or are assigned as dedicated resources. The common or second bitmap pool parameter 335 may be in the form of one or more bitmaps. Only one bitmap is needed when discovery resources are frequency domain multiplexed; two bitmaps can be used when discovery resources are frequency domain multiplexed. In one example, the common discovery resource pool parameter can be a first bitmap indicating common discovery resources and the dedicated discovery resource pool parameter is a second bitmap indicating second bitmap when the discovery resources discovery are multiplexed by time domain. At block 1335, method 1300 may include receiving a transmission resource selection method parameter 360. Transmission resource selection method parameter 360 may indicate a method to be used by the user device for selecting which of the Discovery available resources should be used for discovery signal transmission. At block 1340, method 1300 may include receiving a DMRS usable cyclic shifts parameter 365. DMRS usable cyclic shifts parameter 365 may indicate that DMRS cyclic shifts are available and the time variation pattern of the DMRS time variation pattern. DMRS cyclic changes.

[000133] At block 1345, method 1300 may include using any one or more of the received parameters to participate in D2D discovery. Received parameters can be used for example by a user device in order to use discovery features. While method 1300 can be followed as illustrated in Fig. 13, the order of reception and types of parameters need not be limited to the specific order of reception and types of parameters identified in Fig. 13. In other words, blocks 1305-1340 can occur in different orders and not all of the parameters indicated by these blocks can be received before the use of any one or more of the parameters received in block 1345 takes place.

[000134] In other examples of method 1300, the user device may receive some or all of a plurality of parameters on different frequencies in a system broadcast message. In other examples, the user device may receive some or all of the plurality of parameters for different public land mobile networks in a system broadcast message. In some embodiments, operations at blocks 1305, 1310, 1315, 1320, 1325, 1330, 1335, or 1340 can be performed using the pair discovery module 515 described with reference to Figures 5, 6, 7, or 8.

[000135] Therefore, method 1300 can be used for wireless communication. Note that method 1300 is only one implementation and that the operations of method 1300 may be rearranged or otherwise modified so that other implementations are possible.

[000136] Figure 14 is a flowchart illustrating an example of a method 1400 for wireless communication, in accordance with various aspects of the present description. For clarity, method 1400 is described below with reference to aspects of one or more of the Base Stations 105 described with reference to Figures 1, 2, or 4A, or aspects of one or more of the handsets 905 described with reference to Figures. 9 or 10. In some examples, the base station such as one of the Base Stations 105 or an apparatus such as one of the apparatus 905 can execute one or more sets of codes to control the functional elements of the base station or apparatus to execute the functions described below.

[000137] In block 1405, method 1400 may include transmitting a discovery period parameter 305. The discovery period parameter 305 transmitted identifies a discovery period in which discovery resources are available for D2D discovery. The discovery period parameter 305 passed may also identify multiple discovery periods available for D2D discovery.

[000138] In block 1410, if a transmitted discovery period is a multiple of SFN, then method 1400 may transmit, in block 1415, an SFN length parameter 310. The SFN length parameter 310 may indicate a number of times that the maximum SFN is exceeded during the transmitted discovery period. If the transmitted discovery period is not a multiple of SFN, then method 1400 may not require any transmission of an SFN extension parameter 310. In block 1420, method 1400 may include transmission of a discovery offset parameter 315. Discovery offset parameter 315 may indicate an offset between a start of the discovery period and a reference point based on the fixed time. As an example, the fixed time-based reference point could be when SFN and any extended SFN were equal to zero. In some examples, the discovery offset parameter may indicate an offset between the start of the discovery period and the fixed time-based reference point for both the transmit and receive groups. In some examples, a neighbor receiving group offset may also be indicated with respect to the fixed reference point of a serving cell.

[000139] At block 1425, method 1400 may include transmitting a discovery subframe parameter. The discovery parameter subframe can indicate which subframes within the discovery period are available as discovery resources. The discovery parameter subframe can be in the form of one or more bitmaps.

[000140] In block 1430, method 1400 may include transmitting an RB discovery length parameter 325. The RB discovery length parameter 325 may indicate a number of RBs to be used for each discovery signal within a subframe available as a discovery feature. In block 1435, method 1400 may include transmitting discovery RB start and end point parameters 330. Discovery RB start and end point parameters 330 may be used with discovery RB length parameter 325 to indicate a point start and endpoint of the RBs to be used for each discovery signal within a subframe available as a discovery resource. While method 1400 can be followed as illustrated in Fig. 14, the transmission order and types of parameters need not be limited to the specific transmission order and types of parameters identified in Fig. 14. In other words, blocks 1405-1430 can occur in different orders, and not all parameters indicated by these blocks can be transmitted before the step of using any one or more of the transmitted parameters occurs. In some embodiments, operations at blocks 1405, 1410, 1415, 1420, 1425, 1430, or 1435 can be performed using a discovery parameter assignment module 910 described with reference to Figures 9 or 10.

[000141] Therefore, method 1400 can be used for wireless communication. Note that method 1400 is only one implementation and that the operations of method 1400 may be rearranged or otherwise modified so that other implementations are possible.

[000142] Figure 15 is a flowchart illustrating an example of a method 1500 for wireless communication, in accordance with various aspects of the present description. For clarity, method 1500 is described below with reference to aspects of one or more of the base stations 105 described with reference to Figures 1, 2, or 4A, or aspects of one or more of the handsets 905 described with reference to Figures. 9 or 10. In some examples, the base station such as one of the base stations 105 or an apparatus such as one of the apparatus 905 may execute one or more sets of codes to control the functional elements of the base station or apparatus to execute the functions described below.

[000143] In block 1505, method 1500 may include transmitting a discovery period parameter 305. The discovery period parameter 305 transmitted identifies a discovery period in which discovery resources are available for D2D discovery. The discovery period parameter 305 passed may also identify multiple discovery periods available for D2D discovery. In block 1510, method 1500 may include transmitting modulation and encoding parameters 335.

[000144] The modulation and coding parameters 335 can indicate a modulation and coding scheme for transmission of discovery signal.

[000145] In block 1515, method 1500 may include transmitting a sync signal parameter position 340. The sync signal parameter position 340 may indicate a position of a sync signal from a neighboring base station when that synchronization signal is forwarded by neighboring base station user devices. Thus, the parameter allows a user device to receive the synchronization signal when it is forwarded by another user device. At block 1520, method 1500 may include transmitting a transmit power parameter 345. Transmit power parameter 345 may indicate a power level for transmitting discovery signal. The available discovery resources can be divided into different power zones. When this is the case, transmit power parameter 345 can be used to indicate in which power zone a particular discovery resource is located. Transmit power parameter 345 may be in the form of a bitmap.

[000146] In block 1525, method 1500 may include transmission of an authorized mode of operation parameter 350. Authorized mode of operation parameter 350 may indicate whether discovery may occur during a connected mode or during an idle mode of the device of user. At block 1530, method 1500 may include transmitting a second or common bitmap pool parameter 355. The available discovery resources may be either common or may be dedicated for the use of a specific user device. common or second bitmap pool parameter 355 indicates whether available discovery resources are either common or are assigned as dedicated resources. The second or common bitmap pool parameter 355 may be in the form of one or more bitmaps. Only one bitmap is required when discovery resources are frequency domain multiplexed; two bitmaps can be used when discovery resources are time domain multiplexed.

[000147] In block 1535, method 1500 may include transmitting a transmission resource selection method parameter 360. Transmission resource selection method parameter 360 may indicate a method to be used by a user device for selecting which of the available discovery resources should be used for discovery signal transmission. At block 1540, method 1500 may include transmitting a DMRS usable cyclic shift parameter 365. DMRS usable cyclic shift parameter 365 may indicate which DMRS cyclic shifts are available and the time-varying pattern of DMRS Cyclic Shifts .

[000148] Although method 1500 can be followed as illustrated in Figure 15, the transmission order and types of parameters need not be limited to the specific transmission order and types of parameters identified in Figure 15. In other words, blocks 1505-1540 may occur in different orders and not all parameters indicated by these blocks may be transmitted before the step of using any one or more of the transmitted parameters occurs. In other examples, only a subset of the parameters shown in Figure 15 can be passed. In some embodiments, operations at blocks 1505, 1510, 1515, 1520, 1525, 1530, 1535, or 1540 can be performed using discovery parameter assignment module 910 described with reference to Figures 9 or 10.

[000149] Therefore, method 1500 can be used for wireless communication. Note that method 1500 is only an implementation and that the operations of method 1500 can be rearranged or otherwise modified so that implementations are possible.

[000150] The detailed description, set out above, in connection with the attached drawings presents embodiments by way of example and does not represent only the embodiments that can be implemented or that are within the scope of claims. The detailed description includes specific details for the purpose of providing further clarity of the described techniques. These techniques, however, can be practiced without these specific details. In some examples, well-known structures and devices are shown in the block diagram in order to avoid obscuring the concepts of the described embodiments.

[000151] Techniques described here can be used for various wireless communication systems such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, and other systems. The terms "system" and "network" are often used interchangeably. A CDMA system can implement radio technology such as CDMA2000, Universal Terrestrial Radio Access (UTRA), etc. CDMA2000 covers IS-2000, IS-95, and IS-856 standards. IS-2000 releases 0 and A are commonly referred to as CDMA2000 IX, IX, etc. IS-856 (TIA-856) is commonly referred to as CDMA2000 lxEV-DO, High Rate Packet Data (HRPD), etc. UTRA includes Wideband CDMA (WCDMA) and other variants of CDMA. A TDMA system can implement a radio technology such as Global Communications System for Mobile (GSM). An OFDMA System can implement a radio technology such as Ultra Mobile Broadband (UMB), Evolved UTRA (E-UTRA), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDM, etc. UTRA and E-UTRA are part of the Universal Mobile Tele Communication System (UMTS). 3GPP Long Term Evolution (LTE) and LTE-Advanced (LTE-A) are new releases of UMTS using E-UTRA. UTRA, E-UTRA, UMTS. LTE, LTE-A, and GSM are described in documents from an organization called the "3rd Generation Partnership Project" (3GPP). CDMA2000 and UMB are described in documents from an organization called "3rd Generation Partnership Project 2" (3GPP2). The techniques described here can be used for the above systems and radio technologies as well as other systems and radio technologies. The above description, however, describes an LTE System for purposes of example, and LTE terminology is used extensively in the above description, although the techniques are applicable beyond LTE applications.

[000152] Communication networks that can accommodate some of the various embodiments used may be packet-based networks that operate according to a layered protocol stack. For example, communications on the bearer or Packet Data Convergence Protocol layer can be IP-based. A Radio Link Control (RLC) layer can perform packet segmentation and reassembly to communicate over logical channels. A Medium Access Control (MAC) layer can perform priority management and multiplexing of logical channels into transport channels. The MAC layer can also use Hybrid ARQ (HARQ) to provide retransmission at the MAC layer to improve link efficiency. At the physical layer, transport channels can be mapped to physical channels.

[000153] Information and signals can be represented using any variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that can be referenced throughout the above description can be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination. this one.

[000154] The various illustrative blocks and modules described in connection with the description here can be implemented or executed with a general purpose processor, a DSP, an ASIC, an FPGA or other programmable logic device, discrete port or discrete hardware components , transistor logic, or any combination thereof designed to perform the functions described here. A general purpose processor may be a microprocessor, but alternatively, the processor may be any conventional processor, controller, microcontroller or state machine. A processor may also be implemented as a combination of computing devices, for example a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, as opposed to any other such configuration. A processor may in some cases be in electronic communication with a memory, where the memory stores instructions that are executable by the processor.

[000155] The functions described here can be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, functions may be stored in or transmitted by one or more instructions or code on a computer-readable medium. Other examples and implementations are within the scope of the accompanying description and claims. For example, due to the nature of software, functions described above can be implemented using software executed by a processor, hardware, firmware, hardwiring, or combinations thereof. Feature implementation functions can also be physically located in various locations, including being distributed so that portions of functions are implemented in different physical locations. Thus, as used herein, including in the claims, "or" as used in a list of items indicates a disjunctive list such that, for example, a list of "at least one of A, B, or C" means A or B or C or AB or AC or BC or ABC (i.e., A and B and C).

[000156] A computer program product or computer readable medium include both a computer readable storage medium and communication medium, including any means that facilitate the transfer of a computer program from one location to another. A storage medium can be any medium that can be accessed by a special or general purpose computer. By way of example, and without restrictive crater, computer-readable medium may comprise RAM, ROM, EEPROM, CD-ROM or other storage devices on optical disk, magnetic disk or elsewhere, or any other medium that may be used to or store computer-readable program code in the form of instructions or data structures and accessible by a special or general purpose computer, or a general or special purpose processor. Therefore, any connection is properly called a machine-readable medium. For example, if the software is streamed from a website, server, or other remote light source using coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared , radio, and microwave, therefore coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of medium. Floppy disk and disk as used herein include, as used herein, compact disk (CD), laser disk, optical disk, digital versatile disk (DVD), floppy disk and Blu-ray disk where disks usually reproduce data magnetically while disks reproduce data optically with lasers. Combinations of the above are also included within the scope of computer readable medium.

[000157] The previous description of the publication is provided to allow the person skilled in the art to make or use the description. Various modifications to the description will be readily recognized by the person skilled in the art and the generic principles defined herein can be applied to other variations without thereby departing from the scope of the description. Throughout the description the term "example" indicates an example or example and does not imply or require any preference for the registered example. Accordingly, the description should not be limited to the examples and configurations described herein but to be granted the widest consistent scope with the principles and new features described here.

Claims (15)

1. Method for wireless communication, characterized in that it comprises: receiving (1105) at a user device a plurality of parameters for device-to-device discovery, the plurality of parameters including a discovery period parameter (305) which identifies a discovery period, in which discovery resources are available for device-to-device discovery; wherein at least a subset of the plurality of parameters have values based at least in part on a user device class; and utilizing (1110) the plurality of parameters in order to participate in discovery with other user devices. 2. Method according to claim 1, characterized in that the discovery period is a fraction or a multiple of a maximum number of system frames (SFN) of a network in which the user device is used. 3. Method according to claim 2, characterized in that when the discovery period is a multiple of a maximum SFN, the plurality of parameters also includes an SFN length parameter (310) to indicate a number of times that the maximum SFN is exceeded during the discovery period. 4. Method according to claim 1, characterized in that the plurality of parameters also comprises a discovery offset parameter (315) that indicates an offset between a start of the discovery period and a fixed reference point based on the time for a resource pool, the method further comprising: indicating a neighboring resource pool offset with respect to a time-based fixed reference point to a serving cell of the user device. 5. Method according to claim 1, characterized in that the plurality of parameters also includes a discovery subframes parameter (320) which indicates which subframes within the discovery period are available as discovery resources. 6. Method according to claim 5, characterized in that the discovery subframe parameter (302) is a bitmap. 7. Method according to claim 5, characterized in that the plurality of parameters also includes discovery resource block start point and end point parameters that indicate a start point and an end point of one or more blocks of resources to be used for each discovery signal within a subframe available as a discovery resource. Method according to claim 1, characterized in that the plurality of parameters also includes a sync signal parameter position (340) that indicates a position of a sync signal from a base station as transmitted each discovery period by one or more user devices connected to the base station. 9. Method according to claim 1, characterized in that the plurality of parameters also includes a transmit power parameter that indicates a power level for transmitting the discovery signal. 10. Method according to claim 1, characterized in that the plurality of parameters includes two or more of a system frame number (SFN) extension parameter, a discovery offset parameter, a subframe parameter discovery feature, a discovery feature block length parameter, discovery feature block start point and end point parameters, modulation and encoding parameters, a sync signal parameter position, a transmission, an authorized mode of operation parameter, a common discovery resource pool parameter, and a dedicated discovery resource pool parameter, where the user device class is one of commercial security or public safety. 11. The method of claim 1, characterized in that receiving (1105) the plurality of parameters also comprises receiving: some of the plurality of parameters at different frequencies in a system broadcast message; or the plurality of parameters for different public land mobile networks (PLMNs) in a system broadcast message. 12. Apparatus for wireless communication, characterized in that it comprises: means for receiving (1105), at a user device, a plurality of parameters for device-to-device discovery, the plurality of parameters including a discovery period parameter (305) identifying a discovery period, in which discovery resources are available for device-by-device discovery; wherein at least a subset of the plurality of parameters have values based at least in part on a user device class; and means for utilizing (1110) the plurality of parameters in order to participate in discovery with other user devices. 13. Apparatus according to claim 12, characterized in that the means for receiving includes means for receiving a system frame number (SFN) extension parameter (310) to indicate a number of times a maximum SFN is exceeded during the discovery period. 14. Apparatus according to claim 12, characterized in that the means for receiving include means for receiving a discovery offset parameter (315) that indicates an offset between a start of the discovery period and a fixed reference point time-based reference point for a resource pool, the apparatus further comprising: means for indicating a neighboring resource pool offset with respect to a fixed time-based reference point to a serving cell of the user device. 15. Computer-readable memory characterized by the fact that it comprises instructions stored therein that, when executed, cause the computer to perform the method as defined in any one of claims 1 to 11.

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